class Person {
  constructor() {
    this.name = "merci"
    this.info = {
      "age": 18
    }
  }
}
Person.prototype.name2 = "name2"
Person.prototype.info2 = {
  "age2": "18"
}

let p1 = new Person()
let p2 = new Person()

p1.name = "p1"
p1.info.age = "25"
console.log(p2.name, p2.info.age);

p1.name2 = "p1"
p1.info2.age2 = 25

console.log(p2.name2, p2.info2);